package com.fast.web.security;

import java.io.Serializable;

import javax.annotation.PostConstruct;

import org.apache.shiro.authc.AuthenticationException;
import org.apache.shiro.authc.AuthenticationInfo;
import org.apache.shiro.authc.AuthenticationToken;
import org.apache.shiro.authc.DisabledAccountException;
import org.apache.shiro.authc.SimpleAuthenticationInfo;
import org.apache.shiro.authc.UsernamePasswordToken;
import org.apache.shiro.authc.credential.HashedCredentialsMatcher;
import org.apache.shiro.authz.AuthorizationInfo;
import org.apache.shiro.authz.SimpleAuthorizationInfo;
import org.apache.shiro.realm.AuthorizingRealm;
import org.apache.shiro.subject.PrincipalCollection;
import org.apache.shiro.util.ByteSource;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;

import com.fast.domain.SysUser;
import com.fast.service.UserService;
import com.fast.web.utils.Encodes;
import com.google.common.base.Objects;

public class ShiroDbRealm extends AuthorizingRealm {
	private final Logger logger = LoggerFactory.getLogger(getClass());
	
	@Autowired
	protected UserService userService;

	/**
	 * 认证回调函数,登录时调用.
	 */
	@Override
	protected AuthenticationInfo doGetAuthenticationInfo(
			AuthenticationToken authcToken) throws AuthenticationException {
		logger.info("doGetAuthenticationInfo(AuthenticationToken authcToken)");
		UsernamePasswordToken token = (UsernamePasswordToken) authcToken;
		SysUser user = userService.findUserByLoginName(token.getUsername());

		if (null == user) {
			return null;
		}

		if ("1".equals(user.getDelFlag())) {
			throw new DisabledAccountException();
		}

		byte[] salt = Encodes.decodeHex(user.getSalt());
		return new SimpleAuthenticationInfo(new ShiroUser(user.getLoginName(),
				user.getName()), user.getPassword(),
				ByteSource.Util.bytes(salt), getName());
	}

	/**
	 * 授权查询回调函数, 进行鉴权但缓存中无用户的授权信息时调用.
	 */
	@Override
	protected AuthorizationInfo doGetAuthorizationInfo(
			PrincipalCollection principals) {
		logger.info("doGetAuthorizationInfo(PrincipalCollection principals)");
		ShiroUser shiroUser = (ShiroUser) principals.getPrimaryPrincipal();
		SysUser sysUser = userService.findUserByLoginName(shiroUser.loginName);

		SimpleAuthorizationInfo info = new SimpleAuthorizationInfo();
		// for (Role role : user.getRoleList()) {
		// // 基于Role的权限信息
		// info.addRole(role.getName());
		// // 基于Permission的权限信息
		// info.addStringPermissions(role.getPermissionList());
		// }
		return info;
	}

	/**
	 * 设定Password校验的Hash算法与迭代次数.
	 */
	@PostConstruct
	public void initCredentialsMatcher() {
		logger.info("initCredentialsMatcher()");
		HashedCredentialsMatcher matcher = new HashedCredentialsMatcher(
				UserService.HASH_ALGORITHM);
		matcher.setHashIterations(UserService.HASH_INTERATIONS);
		setCredentialsMatcher(matcher);
	}

	/**
	 * 自定义Authentication对象，使得Subject除了携带用户的登录名外还可以携带更多信息.
	 */
	public static class ShiroUser implements Serializable {
		private static final long serialVersionUID = -1373760761780840081L;
		private String loginName;
		private String name;

		public ShiroUser(String loginName, String name) {
			this.loginName = loginName;
			this.name = name;
		}

		public String getName() {
			return name;
		}

		/**
		 * 本函数输出将作为默认的<shiro:principal/>输出.
		 */
		@Override
		public String toString() {
			return loginName;
		}

		/**
		 * 重载hashCode,只计算loginName;
		 */
		@Override
		public int hashCode() {
			return Objects.hashCode(loginName);
		}

		/**
		 * 重载equals,只计算loginName;
		 */
		@Override
		public boolean equals(Object obj) {
			if (this == obj) {
				return true;
			}
			if (obj == null) {
				return false;
			}
			if (getClass() != obj.getClass()) {
				return false;
			}
			ShiroUser other = (ShiroUser) obj;
			if (loginName == null) {
				if (other.loginName != null) {
					return false;
				}
			} else if (!loginName.equals(other.loginName)) {
				return false;
			}
			return true;
		}
	}
}
